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TitaniumDragon t1_iv192de wrote

Reply to comment by joshdykgraaf in Wayamba, Me, Digital, 2022 by joshdykgraaf

Back during the last ice age, global temperatures were far lower than they are today, but many species used this sort of temperature dependent gender determination.

These species still exist today, even though global temperatures have changed by more than 4C since the last ice age - well beyond the range in question.

If you spend a few moments thinking, you'll realize immediately that these things don't match up. Why aren't these species already extinct? The Bølling–Allerød interstadial and Younger Dryas surely would have killed them off.

The answer is, of course, that the "logic" is wrong.

IRL, what actually happens is a few things.

First off, species can migrate north/south. When temperatures go up, they can go to more southerly areas that were previously too cold for them; when they go down, they can go to more northerly areas that were previously too hot for them.

Secondly, if you have a mutation that gives you the ability to produce the gender that is less common, your offspring will hyperproliferate. This is especially true in this case, where you end up with more females than males; the males that exist have a ridiculously huge reproductive advantage, which results in extremely strong selection towards producing more male offspring.

It's actually pretty unlikely it will lead to their total extinction, given that they've survived previous large temperature swings in the past.

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DeathByLemmings t1_iv1aycv wrote

While comforting if true I feel like you have a subtext, please correct me and say you were just setting peoples mind at ease on the subject of turtles

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TitaniumDragon t1_iv2e13y wrote

It's really more of a general thing about global warming. Most people don't understand what effects global warming will actually have very well; they don't have a good grasp of what it entails.

Most people have little understanding of the science behind global warming, and instead get their impressions from the popular press, which does a poor job of covering it because journalists aren't scientists. So you get very sensationalist stuff about how everything is going to die, or on the other side, articles about how it is a big nothingburger because the sensationalist stuff doesn't happen or blames every single weather event on global warming.

The actual science of global warming and climate change and modelling the effects is very interesting, but most people don't (and really, can't) read science papers, so they have to rely on intermediaries.

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DeathByLemmings t1_iv2pvvi wrote

Ok, and what are the implications to you then?

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TitaniumDragon t1_iv2zgne wrote

It's an expensive annoying long term problem.

The biggest problem in the extreme long term (hundreds to thousands of years) is the ice caps melting; we aren't sure exactly how long it will take, but it will take a long time (present models suggest we will likely see less than 1 meter of sea level rise in 2100). In the long run, having much higher sea levels (tens of meters higher than present) will be the largest negative consequence due to loss of currently desirable land area.

It will cause a net increase in arable regions and overall increase precipitation, but some areas will get drier and undergo desertification due to a higher evaporation rate and shifts in rainfall patterns. The increase in precipitation will also likely cause increased flooding in some areas, while the increased rate of evaporation and higher temperatures may cause more wildfires.

It will make winters more mild, but it will make summers hotter as well. Ironically, this will probably cause a net decrease in human deaths due to inclement weather; winters kill more people than summers do, and with the continued proliferation of air conditioning, that's likely to get even more extreme. However, it might cause some pests to expand their regions poleward.

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[deleted] t1_iv3a7k2 wrote

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TitaniumDragon t1_iv3qs43 wrote

> The BIG thing you are missing here is the time scale. The transition into and out of the last ice age lasted tens of thousands of years.

This is incorrect, actually.

The transition from ice age to not ice age took only 3,000 years.

But it was actually uneven and even faster than that; I'd recommend clicking on those Wikipedia articles.

The last ice age shifted from glacial conditions to not at the start of the Bølling–Allerød interstadial occurred in perhaps 200 years.

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[deleted] t1_iv3vu83 wrote

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TitaniumDragon t1_iv3ywjv wrote

If you want to extend that out to the full 10C change, that happened between ~17.5kya and ~11.5 kya - a period of about 6,000 years. You could extend that back to 19kya if you are generous and count from the very earliest glacial retreat, which is about 7.5kya

Moreover, there was massive acceleration in the glacial retreat after 15kya. That's what really marked the start of the end of the Ice Age; the vast, vast majority of the melting occurred between 15kya and 11.5kya.

And as noted, there was a massive warming event, that I literally linked you to in my post and that is visible in that graph you linked to, that saw 3 C of warning take place in just a couple centuries.

The idea that the climate only changes very slowly is actually false, and it is the sort of thing that no one with any real comprehension of science claims. It can happen quite fast; 1 C variations in temperature in a century are common, and 3C in a couple centuries has happened.

I'm not sure why you're lying about this, other than because you don't want to admit you're wrong. Even the graph you linked to shows you are wrong.

https://en.wikipedia.org/wiki/B%C3%B8lling%E2%80%93Aller%C3%B8d_warming

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